Your questions are frequently asked here and have been answered in numerous threads. Would suggest that you go to the search box at the top of the page and type in "shallots" -

And the nicer answer is, plant in the fall. Taste is like a mild onion. Best? Don't know about that, I've tried several.

Dig some composted manure into the soil before you plant. Alliums defy the usual story that root crops like lean soil. Alliums actually are more like grass, and like a lot of nitrogen. So plant in a manured soil, with the point of the shallot just below the soil, then mulch with your favorite material. I use oak leaves and cover them with pine straw to hold them down in winter winds. Why those materials? Because I have oak brush and pine trees in my yard, so that is what is available. I may also get a bale of straw this fall and try that in some places, just because my garden has outgrown my mulching materials.

I have found the shallots available in my local grocery store are now the variety grown from seed, and if you plant the nice big bulbs this fall, they will go to seed next summer. Not quite what I was looking for, so I didn't look to see if they behaved like potato onions and also still had a bulb that divided.

So on to other fall-planting onions. Bunching onions can be fall-planted. Like shallots, garlic, and potato onions, bunching onions divide into a clump. They are non-bulbing, so they end up looking like the green onions/scallions sold in the grocery store. In fact, some of those green onions ARE bunching onions, but you never know which ones. Potato onions I sort of touched on. Think of them as large shallots. They don't produce as large an onion as spring-planted bulbing onions, but they are always available and keep well. Plant the large bulbs to divide into clumps, plant the small bulbs to grow into larger bulbs. Garlic, of course, is planted in the fall, try some from your local farmer's market or organic food store (we are always warned that garlic from the grocery store may be sprayed with growth inhibitors, although I have never had any trouble having it grow eventually--it probably isn't suited to your climate/latitude/etc though if it is from China or Gilroy, CA).

Good Luck

Catherine